Electrical supply box



FIG. 1 is a top, front, left side perspective view of an electrical supply box, showing my new design;

FIG. 2 is a front view thereof;

FIG. 3 is a back view thereof,

FIG. 4 is a top view thereof;

FIG. 5 is a bottom view thereof;

FIG. 6 is a left side view thereof; and,

FIG. 7 is a right side view thereof.

The broken lines in the drawings depict portions of the electrical supply box that form no part of the claimed design. 

CLAIM The ornamental design for a electrical supply box, as shown and described. 